Source : Webster's Revised Unabridged Dictionary (1913)

Lemon \Lem"on\ (l[e^]m"[u^]n), n. [F. limon, Per. l[imac]m[=u]n;
   cf. Ar. laim[=u]n, Sp. limon, It. limone. Cf. {Lime} a
   fruit.]
   1. (Bot.) An oval or roundish fruit resembling the orange,
      and containing a pulp usually intensely acid. It is
      produced by a tropical tree of the genus {Citrus}, the
      common fruit known in commerce being that of the species
      {C. Limonum} or {C. Medica} (var. Limonum). There are many
      varieties of the fruit, some of which are sweet.

   2. The tree which bears lemons; the lemon tree.

   {Lemon grass} (Bot.), a fragrant East Indian grass
      ({Andropogon Sh[oe]nanthus}, and perhaps other allied
      species), which yields the grass oil used in perfumery.

   {Lemon sole} (Zo["o]l.), a yellow European sole ({Solea
      aurantiaca}).

   {Salts of lemon} (Chem.), a white crystalline substance,
      inappropriately named, as it consists of an acid potassium
      oxalate and contains no citric acid, which is the
      characteristic acid of lemon; -- called also {salts of
      sorrel}. It is used in removing ink stains. See {Oxalic
      acid}, under {Oxalic}. [Colloq.]

Source : WordNet®

lemon sole
     n 1: flesh of American flounder; important in the winter [syn: {winter
          flounder}]
     2: highly valued almost pure white flesh [syn: {English sole}]
     3: popular pale brown food flatfish of the Pacific coast of
        North America [syn: {English sole}, {Parophrys vitulus}]
     4: small European sole [syn: {Solea lascaris}]
     5: European flatfish highly valued as food [syn: {Microstomus
        kitt}]
     6: important American food fish in the winter [syn: {winter
        flounder}, {blackback flounder}, {Pseudopleuronectes
        americanus}]